A post on the Doom9 forums has claimed to have found another set of device keys crucial to the unlocking of the AACS copy protection used by both Blu-ray and HD DVD discs.

The device key in question was found using the software playback program WinDVD 8. The poster who claims to have found the device keys is registered under the name "ATARI Vampire," and says that he has been "actively sitting in the shadows for the last six to eight weeks" following the efforts of other hackers, specifically muselix64 and arnezami. The former created a software program called BackupHDDVD that decrypted high-definition media content, but did not supply any of the necessary encryption keys to do so. The latter found a method of extracting the Volume ID signatures from any HD DVD or Blu-ray disc. ATARI Vampire found that he could work backwards using these two methods to extract the device keys from memory while WinDVD 8 was running.

This completes all the necessary elements for cracking and decrypting any Blu-ray or HD DVD disc and creating an unprotected version of the content. One caveat, however: the method arnezami used to find Volume License Keys must still be used for each new disc. The true "last piece of the puzzle" that would allow anyone to crack any disc without using any memory scanning methods is to find the Host Private Key that is used to turn the Volume ID on each disc into the Volume License Key. The hunt is now on for this last key, but it has not been found yet.

Does this latest crack mean that AACS has failed? Not exactly. The creators of the AACS encryption predicted that keys would leak out, which is why they added a provision to the spec for revoking the device keys of any player that had been compromised. The Host Private Key can also be revoked under the spec. New discs manufactured after this revocation will simply refuse to play on devices that have been revoked. For a software player such as WinDVD 8, this is particularly easy, as the software can simply demand an update over the Internet.

Still, the methods used to find these device keys in the first place could theoretically be used to extract new ones. The software manufacturers may then be tasked by the content providers to harden their programs to resist these sorts of attacks. This may explain why the device keys for PowerDVD and WinDVD have not yet been revoked.

As far as the legality of cracking AACS protection, that is still very much up in the air, and depends on laws which seem to be changing every day. Recently, Sourceforge removed the open-source BackupHDDVD utility from their servers after they received a DMCA takedown notice.

From ars technica